| Tempol prevents altered K(+) channel regulation of afferent arteriolar tone in diabetic rat kidney. | |
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MedLine Citation:
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PMID: 22252401 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Experiments were performed to test the hypothesis that oxidative stress underlies the enhanced tonic dilator impact of inward-rectifier K(+) channels on renal afferent arterioles of rats with streptozotocin-induced diabetes mellitus. Sham and diabetic rats were left untreated or provided Tempol in their drinking water for 26±1 days, after which afferent arteriolar lumen diameter and its responsiveness to K(+) channel blockade were measured using the in vitro blood-perfused juxtamedullary nephron technique. Afferent diameter averaged 19.4±0.8 μm in sham rats and 24.4±0.8 μm in diabetic rats (P<0.05). The decrease in diameter evoked by Ba(2+) (inward-rectifier K(+) channel blocker) was 3 times greater in diabetic rats than in sham rats. Glibenclamide (K(ATP) channel blocker) and tertiapin-Q (Kir1.1/Kir3.x channel blocker) decreased afferent diameter in diabetic rats but had no effect on arterioles from sham rats. Chronic Tempol treatment prevented diabetes mellitus-induced increases in both renal vascular dihydroethidium staining and baseline afferent arteriolar diameter. Moreover, Tempol prevented the exaggeration of afferent arteriolar responses to Ba(2+), tertiapin-Q, and glibenclamide otherwise evident in diabetic rats. Preglomerular microvascular smooth muscle cells expressed mRNA encoding Kir1.1, Kir2.1, and Kir6.1. Neither diabetes mellitus nor Tempol altered Kir1.1, Kir2.1, Kir6.1, or SUR2B protein levels in renal cortical microvessels. To the extent that the effects of Tempol reflect its antioxidant actions, our observations indicate that oxidative stress contributes to the exaggerated impact of Kir1.1, Kir2.1, and K(ATP) channels on afferent arteriolar tone during diabetes mellitus and that this phenomenon involves posttranslational modulation of channel function. |
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Authors:
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Carmen M Troncoso Brindeiro; Pascale H Lane; Pamela K Carmines |
Publication Detail:
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Type: Comparative Study; Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't Date: 2012-01-17 |
Journal Detail:
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Title: Hypertension Volume: 59 ISSN: 1524-4563 ISO Abbreviation: Hypertension Publication Date: 2012 Mar |
Date Detail:
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Created Date: 2012-02-20 Completed Date: 2012-04-17 Revised Date: 2012-04-30 |
Medline Journal Info:
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Nlm Unique ID: 7906255 Medline TA: Hypertension Country: United States |
Other Details:
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Languages: eng Pagination: 657-64 Citation Subset: IM |
Affiliation:
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Department of Cellular and Integrative Physiology, University of Nebraska College of Medicine, Omaha, NE, USA. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Antioxidants / pharmacology Arterioles / drug effects, metabolism*, physiopathology Blotting, Western Cyclic N-Oxides / pharmacology* Diabetes Mellitus, Experimental / drug therapy, metabolism* Gene Expression Regulation / drug effects Kidney Cortex / blood supply* Male Muscle, Smooth, Vascular / drug effects, metabolism Oxidative Stress Potassium Channels, Inwardly Rectifying / drug effects, genetics, metabolism* RNA / genetics Rats Rats, Sprague-Dawley Reverse Transcriptase Polymerase Chain Reaction Spin Labels |
| Grant Support | |
ID/Acronym/Agency:
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DK071152/DK/NIDDK NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/Antioxidants; 0/Cyclic N-Oxides; 0/Potassium Channels, Inwardly Rectifying; 0/Spin Labels; 2226-96-2/tempol; 63231-63-0/RNA |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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